Porosity is the ability of the hair to absorb water and other matter (like chemicals).
In the post ‘Balancing Moisture & Protein’, i gave a brief summery of what hair is. The outer layer of the hair, the Cuticle, is made up of several layers of interlocking scales and is responsible for how porous the hair is.
Different Degrees of Porosity
Low or poor porosity is characterised by very tightly closed cuticles and is generally considered healthy as all or most of the cuticle layer is intact. It doesn’t easily absorb water and resists the penetration of chemical treatments.
Normal Porosity is hair that is able to absorb water well but resists permitting too much water to penetrate. This is considered the best porosity to have. Again, all or most of the cuticle layer is in tact and lies down flatly. Hair with normal porosity can hold styles well and receives chemical processing well. Although chemical processes can change the porosity of the hair from average to high.
Highly porous hair is hair that has sustained cuticle damage with lifted, missing, cracked or chipped cuticles. It absorbs significantly higher amounts of water then normal or low porosity hair (up to 55%, in contrast with 31.1% for healthy hair) and is not capable of holding onto that water as the damaged cuticles allow water out just as fast. This type of hair never feels properly moisturised even with constant moisturising. When hair is fully soaked in water, the weight of the excessively absorbed water can lead to significant breakage due to loss of elasticity. Highly porous hair easily accepts chemical treatments such as dyes, but wont hold onto the colour for very long and is easily over processed as it takes significantly less time than low or average porosity types to receive the chemicals. Highly porous hair doesn’t hold onto styles as well as normal or low porosity types.
Uneven porosity is a combination of low or average porosity and high porosity and is common in long hair. The longer your hair is, the older it is and the more it has been exposed to mechanical, chemical, environmental and heat damage. Uneven porosity has spotty issues where some parts of your hair hold onto moisture well and some parts (such as the ends) do not.
What Causes Highly Porous Hair?
Genetics does have a part to play with how porous the hair is. Naturally curly hair is more porous than straight hair by nature. Every kink and bend along the shaft where the hair naturally curls or kinks stops the cuticles from lying down flatly and so the cuticles remain slightly raised along these points. The curlier or kinkier your hair is the more porous it is. Other determining factors are mechanical damage caused by rough handling, dry combing/brushing, friction caused by towel drying, scarfs, hair bands and hats, chemicals such as permanent dyes, relaxers, texturisers and perms, heat damage from tools such as blow-dryers, flat irons and curling tongs as well as over exposure to environmental factors such as UV rays and harsh winds. Strong sulfate shampoos, such as sodium lauryl sulfate, are capable of dissolving the fatty acid layer beneath the cuticle (called the Cell Membrane Complex or CMC, the ‘cement’ that keeps the cuticles in place), which can lead to irreparable gaps in the cuticle layer. Natural soaps, being very alkaline in nature, causes the hair to swell and the cuticle to lift up away from the surface of the hair shaft, penetrating through the cuticle and into the CMC where it can bind with the fatty acid layer and rinse it away, again causing gaps within the cuticles. All these different factors can permanently alter, raise and/or damage the cuticle layer causing highly porous hair.
It is best test for porosity on freshly cleaned and dried hair.
Test One – The Finger Touch Test
Gently hold a few strands of hair with one hand. With the other, run your fingers up the length of your hair, from tip to root. If your hair feels rough with lots of little ridges or bumps (excluding the bumps that are naturally created by the bends in the shaft where the hair curls) then your cuticles are not lying flatly and your hair is porous.
There are some who argue that the first test is not at all effective at determining porosity as the cuticle layers are so microscopically tiny that you can’t possibly feel whether they are raised or not unless the hair has sustained significant damage.
Test Two – The Water Test
Take some shed hair (or pull out a strand of freshly washed and dried hair), a stop watch and a tall glass of water. Drop the hair into the glass and wait for one minute. After the minute has passed check to see whether your hair is floating or has sunk. If your hair is floating ON TOP of the water, than you have low/poor porosity. If your hair is floating JUST UNDER the water, your hair has average porosity. If your hair has SUNK to the bottom of the cup then your hair is highly porous. If part of your hair is FLOATING and part of it is SINKING, you have spotty porosity issues.
Healthy hair should not sink at all or only sink slightly (in one minute that is). The rate that the hair sinks is an indication of how quickly it absorbs (and will lose) moisture. The faster the moisture is absorbed into the hair, the more porous it is. Hair should naturally absorb moisture at a slow pace and should be capable of holding it for long periods of time. If hair absorbs enough moisture within one minute to cause it to sink in water, it is absorbing too fast and indicates high porosity.
Correcting Porosity Issues
After you have determined whether your hair has low, average or high porosity you may be wandering how to correct any issues. Here are some suggestions
If you find your hair does not absorb water well than you need to focus on moisture rich products more than protein. Deep conditioning WITH HEAT (a hooded dryer) is highly recommended. The heat will cause the cuticles to open and will allow the much needed moisture to enter into the cortex.
Highly porous hair can be treated in two ways depending on the type of damage caused to the cuticle.
Lifted Cuticles – PH
If your hair is highly porous and you don’t necessarily use chemicals or heat and are generally quite gentle with your strands then it is possible that the cuticles are raised. Rebalancing your hair’s pH may be all that is required to help return your porosity level to normal. Acidic rinses such as Apple Cider Vinegar (ACV) rinses are an effective way of bringing the pH of your hair back down to optimal levels, thus closing your cuticles and correcting high porosity. For more on pH and hair click HERE.
Damaged Cuticles – Protein
If your hair is highly porous and you regularly use heat and/or chemicals, brush or comb your hair very roughly and/or without slippery products such as conditioner or you have tried correcting your porosity with pH and it hasn’t really helped, then you have sustained cuticle damage. You may have missing, cracked or chipped cuticles. You cannot permanently repair damaged hair but you can patch it up temporarily with protein treatments. Protein helps to reinforce the hairs structure and can help fill in the gaps where the cuticles are chipped or missing. This creates a complete layer over your cortex that can resist moisture loss, keeping the hair moisturised for longer and will help to correct high porosity. Again heat can and should be used to help create stronger bonds between the protein and your hair so that the protein is not simply washed down the drain but actually remains on your hair after rinsing.
Uneven porosity can be corrected by either or both of the suggestion listed above. Using pH and protein will help fill in or flatten the cuticles in those places that are causing the spotty porosity problems. Product layering can also be very effective where the porosity issues are uneven, such as at the ends. If you have dry ends, then layering more moisture and oil/butter on the ends will help to create a thicker barrier where your hair is most susceptible to moisture loss and will help your hair retain moisture evenly.
The Best Treatment of All
I’m sure you know what i’m about to say. Prevention is better then cure! Reducing those things can cause the hair to sustain damage is the best ‘treatment’ we could possibly administer.
- Treat your hair gently.
- Detangle only when your hair is loaded with conditioner to reduce damage caused by friction
- Avoid chemical treatments as much as possible
- Avoid the overuse of heat styling tools
- Avoid harsh sulfate shampoos and alkaline soaps
This brings us to the end of the ‘Getting To Know Your Hair Series’. I hope you’ve enjoyed learning about the different things that can affect the hair and what it takes to keep it healthy. Knowledge is the best tool in any successful hair journey!
If you have any comments, suggestions or questions regarding anything we’ve discussed in this series, feel free to leave them in the comment boxes or email me at NaturalHair.Advice@gmail.com.